It is known that structures which use test tubes for the purposes described above use a chromatic code to distinguish different types of content, or different uses or treatment of the test tubes.
Test tubes are known that for this purpose have closing means, with predefined colors, which facilitate cataloging and recognition.
Test tubes are also known, in particular those intended for cryogenic treatments in nitrogen, to which an identification code is associated, either obtained directly or on a disc, which acts as a support element for the code, applied on the bottom of the test tubes. The code allows to identify, both easily and accurately, by means of automatic systems, the content or the specific use for that test tube, which is essential to avoid errors which can even have serious consequences.
In the case where the disc is applied, that is, to make the bottom so that it can carry the code, there are different systems which comprise co-extrusion or application or gluing.
In the case of application, a considerable precision is required in construction and it is also necessary to achieve a considerable applicative precision. Indeed the gluing or application under pressure must be such as to make the surfaces of the disc where the identification code is applied and those of the test tube which are in reciprocal contact adhere perfectly. This is necessary so as to prevent the liquid nitrogen being introduced between the disc and the test tube when the test tube is introduced into the cryogenic vat. If this happens, it is possible that, once the test tube is extracted, the nitrogen may explode, even eliminating the disc, depriving the test tube of its own identification device.
Indeed, the thrust exerted axially on the disc is considerable, because of the violent reaction that involves the nitrogen in its passage from liquid to gas, in contact with the air, which passage is characterized by a volumetric expansion factor equal to about 1:700.
Because of the nature of the processes needed to make said coupling precision, as well as the solidity of the coupling, said test tubes are costly.
One purpose of the present invention is therefore to make a test tube that allows to speed up the production process and the application on the test tube of the support element where the identification code is applied, thus reducing costs and production times.
Another purpose of the present invention is to make a test tube which can be identified and catalogued easily and quickly using a support element, on which the identification code is applied, which is reliable and resistant to passages from the low temperatures typical of cryogenics to environmental temperature.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.